Software

[Robert Eberlein]

News about software including new version releases.

[Scott Fortmann-Roe]

OAKLAND, California - Your Lingua is pleased to announce the release
of version 2.5 of its powerful modeling software, Simgua, and the
inauguration of support for Windows.

Simgua is an easy to use, yet very extensible scientific simulation
package implementing System Dynamics modeling techniques. In addition
to advanced features such as the ability to invoke secondary analysis
programs from within Simgua, version 2.5 is the first release to
support Microsoft Windows. Both Windows XP and Windows Vista are
supported. Simgua 2.5 is a free upgrade for users of previous
versions.

Check out Simgua and example models at:
http://simgua.com

Pricing information:
Academic Pricing - $32
Commercial Pricing - $525
Upgrade - Free

[Joanne Egner]

We are pleased to announce the release of STELLA and iThink Version 9.1.2.
Version 9.1.2 includes a number of new features and enhancements that make
it even easier to build, share and learn from models.

Version 9.1.2 features include:

• Simulation performance improvements
• Chained Slider enhancements
• Expanded support for hierarchical modules
• Windows command line support
• New built-in functions
• Custom page sizing options
• Data import/export directly to CSV
• Improved error handling

If you’ve purchased a software license or an Annual Support Contract within
the last 12 months, this important update is available for FREE.

To learn more about Version 9.1.2, visit http://www.iseesystems.com

[Scott Fortmann-Roe]

Your Lingua is pleased to announce the release of Simgua 3.0, the next version of its simulation and modeling tool. Simgua 3.0 contains dozens of new features and this new version builds upon Simgua's tradition of openness and power. The key focuses of this release are:

* Macros
Macros open up a whole new world of increased functionality in Simgua. Like Microsoft Word or Excel, Simgua allows you to create small scripts to automate a repetitive task or carry out advanced data analysis. The possibilities of what can be implemented with Simgua macros is virtually endless. In fact, many of Simgua's core features, such as the new Risk Assessment functionality, are written with macros!

* Arrays
Simgua's new array functionality allows you to easily add depth to your model. Say you were modeling the populations of a number of different species of fish within a lake. Without arrays, you would have had to create a separate model for each of the species in the lake. With arrays, however, you create one generic fish model and Simgua transparently manages the duplication for you.

* Risk Assessment
Simgua's built-in risk assessment tools allow users to apply standard, probabilistic methods to assessing risk in System Dynamics models. Based on new research carried out at the Cracow University of Technology, Simgua's risk assessment algorithms will make cost-benefit analyses easier and more accurate.

Simgua 3.0 is free update for owners of previous versions. Commercial licenses may be purchased for $860 and academic licenses may be purchased for $64. Group and classroom discounts discounts are available upon request.

Simgua runs on Mac OS X version 10.4 and above, and on Windows XP and Vista. A 15-day, full-featured trial of Simgua can be downloaded from http://Simgua.com

[Patrick Houel]

Hello,

I'm Patrick Houel, a French engineer, inventor, designer and developer of a systems dynamics software.
I'll tell you about this software began 8 years ago exactly, in December 2001.
The story of my software (called TRUE, Temporal Reasoning Universal Elaboration), began 8 years ago, in December, 2001.

I really can say that True software is the pure result of my imagination because at that time, I did not know anything about the existence of some other softwares such as Vensim or Stella, neither of the stock-and-flow principle. Basically, having no idea about systems dynamics, I consider any similarity to other softwares as being purely coincidental.

One year ago, I found and downloaded the VensimPLE version. Without reading its manual, it took me 3 days to analyze its outcomes and to understand some part of its principles. I discovered then that my own software is based on the classical stock-and-flow principle, just like Vensim and Stella, with some differences, of course. Out of these, the most important are the following:

Related to the Stock-and-Flow principle:


Stocks:
In Vensim, stocks change all together at the same time, only once in the unit time, right before moving on to the next unit of time .
In TRUE, stocks can be changed several times between two consecutive units of time, exactly when it is needed.

Related to the Flows: In Vensim, the calculation of the flow order is an automatic one, strictly depending on the model building. There is "one single clock" for all flows.
In TRUE, the calculation of the flow order is precisely determined by the user, according to the temporal parameters, so that one could manage the cycles of time units by using different “clocks” for each different flow.

The principle used by Vensim permits/allows to easily calculate/compute a model in the continuous mode. For this, the values which change the stocks are divided according to the time step, and the number of time units is multiplied.

If want it, TRUE can operate as Vensim. However, if the model contains several variations of the stocks in the span between two consecutive units of time, the modeling within the continuous mode cannot be an automatic one.

Related to the causal loops:
In Vensim, the static causal loops could be displayed in advance.
In TRUE, there are no causal loops, there are only links dynamically displayed depending on the selected time unit. These links accurately reflect the state of the model at a given time, after all the calculations have been done.

Related to the model outcomes in 2D, 3D and 4D

In TRUE, it is possible to select one unit of time and then to observe and analyze its corresponding values for all the stocks and flows of the model. So, it is possible to directly see in the model the step-by-step evolution of different variables, and therefore learn everything one cannot see in some database listings.

In TRUE, it is also possible to create 3D scenes and then to animate them according to the variables of the model.
These 3D scenes are then turned into 4D scenes, as movies.
The 4D scenes allow the quick check of the behavior of any part of the model.
They also enable the people which are not accustomed with the diagrams to better understand the models.

Thank you for your attention.
My software is featured on the site http://www.true-world.com
from which a free Internet version can be downloaded.


Sincerely.
Patrick Houel

p.s.
Here is a 4D scene

mechanical engineering : piston

TrueRender.gif (618.92 KiB) Viewed 9979 times

[David Sorokin]

Hello,

I’m glad to announce the first stable release of my multi-paradigm simulation library Aivika (http://sourceforge.net/projects/aivika/). It covers System Dynamics, Discrete Event Simulation (both event-driven and process-driven) and the Agent-based modeling. Aivika allows us to create hybrid models and then simulate them. Moreover, the models can be easily integrated into the existent .NET applications. For example, you can create Web-based visualized models using Silverlight. Then such models can be downloaded and played in the Internet browser.

Aivika is mainly destined for modelers who have programmer skills in .NET and the F# programming language. At the same time the domain specific language of Avika in that part which is related to System Dynamics is very close and similar textually to other modeling languages applied in Simtegra MapSys, Vensim, ithink, Powersim, Berkeley-Madonna, AnyLogic and other specialized tools.

For example, let us consider the following simple dynamic system (from tutorial of Berkeley-Madonna):

Code: Select all

   
   STARTTIME = 0
   STOPTIME = 10
   DT = 0.02

   d/dt (A) = - ka*A
   d/dt (B) =ka*A - kb*B
   d/dt (C)  = kb*B
   init A =100
   init B = 0
   init C = 0
   ka =1
   kb =1


In Aivika the same model can be written in the following way (in general-purpose programming language F#):

Code: Select all

  open Maritegra.Aivika
  open Maritegra.Aivika.SD

  let rec a = integ (lazy (-ka * a)) (eta 100.0)
  and b = integ (lazy (ka*a - kb*b)) (eta 0.0)
  and c = integ (lazy (kb*b)) (eta 0.0)
  and ka = 1.0
  and kb = 1.0


Also we can create a value representing the main variables:

Code: Select all

  let system = Dynamics.ofArray [| time; a; b; c |]


To simulate, we need the simulation specs:

Code: Select all

  let specs = {
    StartTime=0.0; StopTime=10.0; DT=0.02;
    Method=RungeKutta4; Randomness=StrongRnd
  }


Now we can start a simulation:

Code: Select all

  let results = Dynamics.run system specs


The results will be

Code: Select all

> results ;;
val it : seq<float []> =
  seq
    [[|0.0; 100.0; 0.0; 0.0|];
     [|0.02; 98.01986733; 1.960397333; 0.01973533333|];
     [|0.04; 96.07894392; 3.843157731; 0.07789834888|];
     [|0.06; 94.17645337; 5.650587164; 0.1729594704|]; ...]


Aivika also allows us to build models based on DES. The simulations can be both even-driven and process-driven. At the same time Aivika allows creating agents in a declarative way similar to that if you defined statecharts. All this can be included in one hybrid model using all three main paradigms: System Dynamics, DES and Agent-based modeling.

By now, the documentation of Aivika describes mainly the topics related to System Dynamics. In the future I’m going to add documentation about using DES and agent-based modeling. At the same, the installation package of Aivika contains sample models for all three paradigms. Each sample has necessary references.

I hope that you will enjoy this small but powerful library which code doesn’t exceed 120 kilobytes!

Best regards
David Sorokin

P.S. Regarding me, the author of Aivika, I developed Simtegra MapSys (http://www.simtegra.com) and MapSim (http://sourceforge.net/projects/mapsim) together with Dr. Zahed Sheikholeslami.

[Tomasz Zawadzki]

Hello there,

As a study over a System Dynamics I have tried to write some cross-platform simulation tool. Actually it's written in Java and is at the very first stage so has only basic simulation features and functions. I hope that in the future it will help to learn and popularize System Dynamics. If you have any suggestions about the software and future recommendations, I will be glad if you share with me. Tool is accessible under the following link:

http://www.optisim.pl/QL/default.asp?iId=KMEHG

Any comments or questions please send to:

tzawa@o2.pl

[Thomas Fiddaman]

Vensim 5.11 is now available for download; highlights include improved help and sample models, documentation tool and SyntheSim enhancements, and bug fixes - see http://www.vensim.com/new.html for details.

[Thomas Fiddaman]

Vensim 5.11a

Vensim 5.11a is now available for download or purchase in the Vensim
store. 5.11a is primarily a bug fix release, correcting issues with
the stats tool, long error messages, and ODBC links, among others.

Refer to the release notes: http://vensim.com/new.html
for more information.

You can upgrade to the latest version of Vensim easily – just follow
the Upgrade link at http://vensim.com/download.html
and enter your license code. Can’t find it? No problem – contact
us for help.

If you're not current with 5.11, there are some interesting new
features, including:

• Significant upgrades to the Help system, including improved
indexing and nearly 100 sample models illustrating the use of almost
every built-in function

• Native Mac support (licenses are portable across platforms)

• GET DIRECT functions that can access spreadsheet data and other
files, like the GET XLS functions, without the overhead of launching
Excel.

• The option of observing integer constraints in the ALLOCATE
AVAILABLE function - great for managing allocation of discrete items
like customers or aircraft.

• Enhancements to the document tool and SyntheSim functionality with
lookups in large models

• On-the-fly configuration of subscripts (arrays) with the GET DIRECT
SUBSCRIPTS or GET ODBC SUBSCRIPTS functions - great for matching model
detail to your data.

• :EXCEPT: statements that let you handle exceptions to subscripted
equations more easily.

20% off Vensim

If you’ve been waiting to move to the premier dynamic modeling tool,
or to extend your maintenance and upgrade to the latest version of
Vensim, now is a great time. All Vensim editions are on sale, 20% off,
through the end of November.

Buy direct at the Vensim store,http://www.vensim.com/store
. At the checkout stage, enter the coupon code NOV11_SALE. For
academic and public research users, please contact us for the
discounts.

Contact sales at vensim@vensim.com <[url]mailto:vensim@vensim.com[/url]>
for volume quotes and other information. Extend your maintenance for
a year of upgrades by logging in with your license key on the download
page, http://www.vensim.com/download.html.

[Toralf Alsaker]

Powersim Studio has been transformed to support both 32-bit and 64-bit operating systems and increased its performance. It has also been given a user interface face-lift.

64-bit Platform Version:
-A new platform version of Powersim Studio targeting 64-bit Windows is now available, allowing for larger models and increased simulation performance.

Premium Edition:
-Powersim Studio 9 introduces the Premium edition targeted towards customers working with very large models.

Features:
-A presentation in Powersim Studio can now be augmented with up to four windows with HTML content, called Presentation Sidekicks. The sidekick windows allow you to add new visual elements and more dynamics to your presentations.
-You can now change the position of a legend for a Time Graph or Chart control.
-It is now possible to import values to start-up variables through datasets.
-In the Premium edition of the 64-bit platform version the maximum number of elements per variable can now be increased to a maximum of 10,000,000 elements.
-You can now create effects for series variables.

Improvements:
-Powersim Studio now conforms to the Unicode standard, with benefits for text input/output in Far East languages, multi-lingual projects, and integration with other applications.
-It is now possible to have up to 1,000,000 runs in a simulation.
-The amount of memory used to store all elements of all variables in the active simulation is now displayed in the Statistics page of the Project Information dialog.
-The user interface of Studio has undergone a facelift. The icons in toolbars, menus, and the various windows of the application are now true color icons.